The present invention relates to an adhesive sheet comprising a base layer, a protective layer disposed on the front surface of the base layer, and an adhesive layer disposed on the back surface of the base layer, which is particularly suited for use as a flooring adhesive sheet, used for the purpose of decorating or protecting the floor surface of buildings.
Generally, flooring materials (e.g., plastic floors, stone material floors, coated floors, wood floors, etc.) disposed on the floor portion in rooms of buildings have a thickness of not less than 2 mm. These flooring materials are usually applied on the floor portion using an adhesive to form a floor surface in rooms of buildings. However, the following problems have occurred on re-application (replacement of floor materials) of these flooring materials.
(a) It is difficult to peel off the flooring material due to its comparatively large thickness, therefore requiring considerable time to replace it.
(b) A larger amount of waste materials are produced corresponding to the increased thickness of the flooring material after it is peeled off.
Therefore, a study has been conducted to use a decorative sheet as a flooring material covering layer. This decorative sheet is a decorative adhesive sheet that is also referred to as a facing sheet, and the total thickness of the sheet is usually less than 1 mm. Although the decorative sheet is often used for interior applications and covering or decorating of walls and ceilings, this study involved attempting to use this decorative sheet for covering a floor surface. Namely, this study was conducted to attempt to solve the above problems (a) and (b) by covering the surface of an applied floor material with a decorative sheet, and replace the decorative sheet instead of reapplying the flooring material.
The surface layer of this type of decorative sheet is typically made of a vinyl chloride resin that is superior in terms of cost and processability. In addition, polyolefin resin is also used for the surface layer. Normally, a printed layer is disposed on the surface layer to form a decorative sheet.
A polyvinyl chloride facing sheet has been proposed as an improved version of this type of decorative sheet in which a vinyl chloride layer is provided on a backing material followed by lamination of a fluorine polymer film as a protective layer thereon by means of an adhesive (Japanese Examined Patent Publication (Kokoku) No. 64-11752 and Japanese Unexamined Patent Publication (Kokai) No. 8-118553, etc.). As a result, this facing sheet has improved stain resistance and scratch resistance. Moreover, it has also been proposed to change the resin layer laminated on a backing material to an acrylic resin emulsion that is free of bleeding (oozing) of plasticizer to improve separation over time from the fluorine polymer film protective layer disposed on its surface (Japanese Patent Publication No. 2512003).
On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 10-175270 teaches an interior facing sheet having superior resistance to staining due to dust. This facing sheet is formed by applying an acrylic resin emulsion to the surface of a backing material and drying the emulsion to a solid to form an acrylic resin layer followed by providing a fluorine polymer layer on the acrylic resin layer that contains an antistatic agent and antifungal agent. Examples of the material of the backing material include organic and inorganic fibers. In addition, an example of an antistatic agent that can be used is polyoxyethylene alkyl phosphate ester surfactant.
In addition, Japanese Unexamined Patent Publication (Kokai) No. 10-95087 teaches an improvement without using any fluorine polymer. The facing paper disclosed in this publication is composed of sequentially laminating a printed layer and a top coat layer on the surface of a paper substrate, the top coat layer comprising a transparent, two-part curable urethane resin containing a polymerized fluorine monomer (oligomer) having a hydrophilic group.
Moreover, Japanese Unexamined Patent Publication (Kokai) No. 6-240201 discloses a surface modifier for coating having superior stain resistance and water repellence, and a coating composition containing the surface modifier for coating. This surface modifier for coating is a fluorinated acrylic resin (polymer or oligomer) composed of, for example, a copolymer obtained by reacting C8F17CH2CH2OCOCHxe2x95x90CH2 and C18H37OCOCHxe2x95x90CH2. A coated film having excellent stain resistance and water repellence can be obtained by adding this surface modifier to a resin for hydroxyl group-containing polyester powder coating, a blocked isocyanate curing agent, a pigment, and dibutyltin laurate, mixing and grinding followed by kneading and grinding the mixture, spraying the coating composition onto a steel plate, and baking the composition for curing to obtain a coated film.
On the other hand, decorative sheets have also been proposed that are capable of preventing the surface of a facing material made of an inorganic plate material from being damaged by abrasion or scratching. For example, Japanese Unexamined Patent Publication (Kokai) No. 11-10823 discloses a decorative sheet in which a specific coating layer (protective layer) is formed on the surface of a substrate having a printed surface, the substrate being made of a plastic sheet or film. For example, the coating layer disclosed in Japanese Unexamined Patent Publication (Kokai) No. 11-10823 is composed of (A) spherical particles (beads) having an average particle diameter of 3 to 50 xcexcm, and (B) a reactive resin, wherein the content of (A) is 5 to 50 wt % based on the total amount of (A) and (B). The above spherical particles are, for example, beads having alumina and so forth as their principal component. A decorative sheet having this type of coating layer effectively enhances the abrasion resistance of the surface in facing materials obtained by laminating the decorative sheet to various types of plate materials, and particularly those obtained by laminating the decorative sheet to inorganic plate materials.
Furthermore, none of the decorative sheets disclosed in the publications explained here were proposed with the intent of using as flooring adhesive sheets.
The present invention provides an adhesive sheet comprising a base layer, a protective layer disposed on the front surface of the base layer, and an adhesive layer disposed on the back surface of the base layer, characterized in that,
the protective layer comprises a surface modifier for modifying the surface of the protective layer, a cured resin and inorganic oxide particles, and the adhesive sheet further comprises a cushion layer comprising an elastomer, disposed between the base layer and the protective layer.
In addition, in another embodiment, the present invention provides a floor surface covered structure comprising a floor of a building, and the above adhesive sheet adhered on the surface of the floor.
This type of adhesive sheet and floor surface covered structure effectively enhances abrasion resistance.